This document is about ChartScale-plugin (Chartscale-pi)
Normally you use the (+) and (-) buttons or the scroll-wheel of your mouse for zooning in and out. But maybe you prefer tou use a slider. The position of the slider (far left, far right or somewhere in between) gives you a direct indication of the zoom-status.
The github repository is:
https://github.com/seandepagnier/chartscale_pi
ChartScale-pi for Windows can be downloaded from this location:
[https://github.com/rgleason/chartscale_pi/releases|Chartscale Executable]]
Click on the most recent to download.
Double-click the downloaded file (with “chartscale_pi” in the name and “.exe” as extension) and follow the set-up instructions.
That's it.
Open (or restart) OpenCPN.
Click Tools-Options-Plugins
Scroll down untill you see the ChartScale-pi.

Click “Enable” to enable the plugin and then “Preferences” to set your preferences (should be self-explanatory).
Click “OK” in the Chart Scale Preferences window and then “OK” in the Plugins-window.
Now the Chart Scale slider should appear on your screen.
In this example the slider-button is to the far left. That means “zoom in as far as possible”.
And in this example the slider-button is to the far right. That means “zoom out as far as possible”.